Today Leo stood unsupported for a few seconds. He had pulled himself up to a standing position at Uma's nightstand with just one hand because he was clutching his straw cup in his other hand when he spotted Kieran's water cup in front of him. He lifted his supporting hand, grabbed Kieran's cup, balanced for three or four seconds, and then carefully lowered himself to a sitting position without dropping either cup. I don't think he realized what he had done, though. He was too intent on trying to fit Kieran's cup in his mouth.
Leo is also quite vocal now. He babbles constantly. Right now it's mostly "ma, ma, ma," "da, da, da," and "ba, ba, ba." He experiments with volume and pitch a lot, too.